Have had exactly this same problem as descibed in my project. Last few versions of the beta it hasn't worked, before that was OK. 'Auto-columns' does work correctly on the grids so there is some level of coms between Architect and the backend. Also Win7-64 with C# backend.

We're having the same problem with Architect. Getting an error "TypeError: 'undefined' is not an objectSource Class: undefined Line 0". Used Charles proxy to debug this error and noticed that the request is not even being sent to the server. We're also seeing deleted objects come back into the project after we save and reopen. The project deploys fine and works fine in the browser. I have to say the Architect is buggy.